Sen. Jeff Flake, R-Ariz., said in a recent interview that he hopes somebody runs against President Trump in the 2020 election, and that Trump supporters' continued chants of "lock her up" — in reference to Hillary Clinton — are "disturbing."

In his retirement interview with C-SPAN, Flake said the chants, which were sparked by Trump's campaign and have continued throughout his presidency, are more concerning than the controversial things Trump says.

"The disturbing thing isn’t so much what [Trump] says anymore, it’s the cheers from people behind him and the chants of, 'Lock her up!'

Flake said he "never did warm" to Trump, and to win a Republican primary election in the U.S. right now, "you have to embrace all of his politics."

The Republican Party "is the president's party right now, no doubt," Flake said.